Abstract

Apodization, which is a tool frequently used for cosmetic representation and efficient modeling of a spectrum, is now also adopted in techniques for the quantitative retrieval of parameters from observed spectra. Whether apodization can help in quantitative spectroscopy is the subject of debate in the literature. We find that, when the considered spectral range is wide enough to accurately model the instrument line shape, the same results can be obtained with and without apodization of the spectrum. However, when a truncation error is introduced by the limited extension of the modeled spectral interval, apodization can efficiently reduce this error. Therefore it is possible to save computing time by using apodization.

Figures (1)

(a) Average ozone retrieved volume mixing ratio profiles relative to MIPAS orbit 2975 calculated by using 15 points for the ILS extension without apodization (dotted curve) and with strong apodization (solid curve). The estimated standard deviations of a single profile are also reported. (b) Differences between each of the two profiles shown in panel (a) and the profile obtained by using 135 points for the ILS extension.